@padluka: As someone pointed out, we have a list of high-risk domains for which we refuse to issue certificates. If you feel that your domain is not high-risk, you can request that it be removed.
I’d also like to repeat what others have said: When you issue a certificate from Let’s Encrypt, it will be disclosed publicly. Make sure to double-check the Privacy Policy to make sure you are okay with that disclosure.
Thanks,
Jacob